1. Field of the Invention
The present invention relates to a liquid crystal display device with a touch panel.
2. Description of the Related Art
A display device having, as an input device, a touch panel that is disposed so as to be overlapped on a display screen of an information communication terminal such as a computer is widely used. Liquid crystal display devices that are generally used as the display device are devices displaying an image by changing an orientation of a liquid crystal composition that is sealed between two substrates of a thin film transistor substrate (hereinafter, referred to as a TFT substrate) and a color filter substrate depending on a change in an electric field and by controlling a degree of transmission of light passing through the liquid crystal composition. Among them, in an In Plane Switching (IPS) system in which both a pixel electrode and a common electrode are disposed on the TFT substrate side, the electrodes forma so-called horizontal electric field and a display having a wide viewing angle is realized.
The touch panel is an input device that causes a processing device to perform a process by recognizing coordinates on a panel that is touched with the fingers of a user and the like. In the touch panel, a resistance film system that detects a change in a resistance value of a portion that is touched, an optical sensor system that detects a change in light intensity of a portion that is blocked by a touch, an electrostatic capacitive coupling system that detects a change in capacitance, and the like are known. The electrostatic capacitive coupling system is widely used because transmittance of the panel is high, display quality is not reduced, and durability thereof is high without coming into contact with other electrodes.
In the related art, a liquid crystal display device with a touch panel of a further thin type is required for satisfying a demand of a miniaturization and a thinning of an information communication terminal. In the liquid crystal display device of the IPS system in JP 2009-244958 A, a liquid crystal display device with a touch panel is disclosed, which is further thinned by using a common electrode of the liquid crystal display device as a driving electrode of the touch panel.